Caster



Patented Apr. 1, 1930 WILFRED G. JOHNSON, or ELYRIA, omo,

.ASSIGNQR T0 THE COLSON COMPANY, GF

ELYRIA, OHIO, A CORPORATION 0F OHIO CASTER Application led December 17, 1927. Serial No. 240,698.

My invention relates to casters and more particularly relates to the attachment of casters to articles of furniture having hollow or tubular legs in such a way that the caster may be made readily detachable or attaehable to legs of varying sizes and forms.

An object of my invention is to provide a caster mechanism adapted to readily attach or provide for detachment of a caster stem receivable into a tubular leg of an article of furniture to the leg in a manner insuring a positive grip against the interior Walls of the leg.

Another object of my invention is to provide improved means for attachment between a caster stem and a tubular leg of an article of furniture adapted to be supported by the caster and which Will insure that the stem will be held substantially axially of the article of furniture at all times.

Another object of my invention is to provide a substantially rigid attachment for a stem held axially within a leg of an article of furniture and which will not be subject to lateral displacement at either end during use of the caster.

Another object of my invention is to provide a mechanism in which the above ob]ects may be accomplished and Which may be manufactured inexpensively but which will` at the same time be eiicient, endurable and inconspicuous in use.

Other objects of my invention and the 'invention itself Will become apparent by reference to the following description of certain embodiments of my invention and which embodiments are illustrated in the accompany* ing drawings. C

Referring to the drawings:

Fig. 1 illustrates an embodiment vof my invention in longitudinal medial sectional.V

view in combination with a caster stem and table leg;

Fig. 2 is a transverse section taken on the line 2-2 of Fig. 1;

sive, at l I show a caster wheel supporting,

on bearings 2, a caster stem 3 rigidly secured to a caster disk 4 resting on the bearings. The stem 3 may be, as shown, reduced at 10 and terminated at 26 in a threaded end. A fragment of table leg is shown at 5, it being assumed in this description that the table leg is better illustrated in Fig. 2 of polygonal tubing and as illustrated, substantially square in cross-sectional form having four sides 6, 7, 8 and 9. The caster stem 3 has also an enlarged polygonal base 11 at its bottom end suitably reduced at 12 so as to be capable (3f projection through the perforation in the cis.: 4.

fr head 13 may be provided by a riveting portion for the reduced portion 12 of the stem to secure the stem to the disk 4. A pair of collars 14 and 15 are provided having tapered annular exterior surfaces 16 and 17 respectively, the collar 14 having a bore of such a size as to permit it to slide freely but snugly over lthe portion 3 of the stem and the collar 15, having an interiorly threaded bore the threads of which are adapted to cooperate withthe threaded end 5 of the caster stein whereby the collar 15 may be reciprocated on the threaded end -of the stem by rotating it in threaded engagement therewith. A pair of twin expander elements 18 are provided, being cut from sheet metal to cruciform shape, the center perforated at 19, and

a plurality of wings, herein shown as four in number, at 20, 21, 22 and 23 folded down in the same direction from the central portion 24. Flange tips 25 for the wings project laterally therefrom. 1 The twin expander ele- `n1ents are each preferably formed alike and are capable of being disposed from the reduced end 4 of the` stem 3 with the edges of their central perforations 19 preferably in spaced relation to the lateral surfaces of the caster stem and with the substantially conical outer surfaces of the collars 14 and 15 proj ected within the wings of the twin expander elements.

It will be noted that in the embodiment illustrated, the outer endsof the flanges 25 are so formed as to fit against the straight sides 6 to 9 inclusive of a square table leg as illustrated, and as indicated by dotted lines in Fig. 2. The same twin elements would fit equally well in a table leg of octagonal section. For table legs of other polygonal sections, twin expander elements having varying number of wings may be employed. The same construction will be capable of being efficiently used in combination with a cylindrical tubular table leg.

In Figs. 4 to 7 inclusive, however, I have,

illustrated a trifurcatcd pair of twin expander elements, each having three wings or expanding forks, the anged tip edges 25 of which may be arcuately formed as illustra-ted for snug engagement with arcuate' surfaces of the interior of the leg. Also in such a construction I contemplate a further feature of improvement providing a roughened surface 24a for the ends or center portion 24 of one or both of the said twin elements. This is to provide for frictional contact between the elements when pressed together so that a flanged collar 14', Fig. 4 may be held by its flange 14 projecting exteriorly of the `tubular leg 5 and at the same time the caster stem 3 may be turned by the polygonal portion 11 projecting through the bore of the collar 14', whereby the collar 15 on the threaded portion of the stem will be caused to move downwardly within the upper expanding element 18 and, the lower expanding element 18a will be pressed downwardly and the inner portions of its wing ends pressed outwardly by the conical surfaces in the collar 14.

Having thus described my invention in its different embodiments, I am aware that numerous and extensive departures may be made from the embodiments herein illus- `trated and described but without departing from the spirit of my invention.

I claim: y y 1. In a caster mechanism, a caster wheel,

`a mounting therefor comprising a bearing,

a caster stem swivelly supported by the bearing on the mounting, said stem having an upper threaded portion, a shoulder on the stem portion disposed adjacent the bearing, a collar adapted to be seated on the shoulder, a second collar disposed on the threaded end of the stem, said collars both having convergingly tapered outer surfaces and a pair of expander elements interposed between the tapered surfaces of the collars, each of said elements comprising a resilient sheet metal stamping having a perforated central portion adapted to be telescoped over the stem end and a plurality of integral wings extending from the same side of the central portion in like angular relation thereto, the ends of the wings of one of said collars of each of said elements adapted to be cammed outwardly by the tapered outer surfaces of a different one of said collars, said expander elements being disposed between the collars with their central portions pressed together by the longitudinal pressure exerted on the ends of the wings by the collars, said stem, said collars and said elements adapted to be projected within the tubular leg of an article of furniture and to have the ends of the wings pressed outwardly by the collars upon rotation of the stem,'one of said collars being held against longitudinal movement in a direction away from the other collar.

2. In a caster mechanism, a caster stem, a wheel swivellable thereon, means to secure the stem within a hollow leg of an article supported by the caster comprising a pair of cone elements disposed on the stem, one of said cone elements being threaded thereon, and adapted to be reciprocated toward the other element when the stem is rotated and a pair of expander elements disposed in longitudinal axial alignment between the cone elements, said expander elements comprising a plurality of wings, the wings of the one element extending divergently from the wings of the other element` said cones, when the threaded cone is advanced, wedging the wings outwardly against the inner surfaces of the leg, and means interlocking said extending elements so as to prevent relative rotation thereof.

3. In a caster mechanism, a caster stem, a wheel swivelable thereon, means to secure the stem within the hollow leg of an article supported by the caster comprising a relatively axially movable pair of elements disposed on the stem, one of said elements being threaded thereon, and adapted to be reciprocated toward the other element upon relative rotation of the stem and said element, one of said elements presenting a converging outer surface toward the other element,` an expander element disposed in longitudinal axial alignment between the elements, said expanderl element of sheet metal having a perforated center through which said stem is projected and integrally radially extending inherently resilient wings extending from the central portion spaced from its perforation and deflected angularly from the same side of the blank, said elements upon movement toward each other by Wedging engagement of the said converging surface of said one element against the inner surfaces of said wings near their ends Wedging the Wings outwardly against the inner surfaces of the In testimony whereof I hereunto aiiix my signature this 21st day of November, 1927. WILFRED G. JOHNSON. 

